feat: added StartTime to ManualTimeProvider

CHANGELOG.md

@@ -5,6 +5,10 @@ All notable changes to TimeScheduler will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.0-preview.4]
+
+- Added 'StartTime' to `ManualTestProvider`, which represents the initial date/time when the `ManualtTimeProvider` was initialized.
+
 ## [1.0.0-preview.3]
 
 - Changed `ManualTestProvider` sets the local time zone to UTC by default, provides method for overriding during testing.

src/TimeProviderExtensions/ManualTimeProvider.cs

@@ -26,6 +26,11 @@ public class ManualTimeProvider : TimeProvider
     private DateTimeOffset utcNow;
     private TimeZoneInfo localTimeZone = TimeZoneInfo.Utc;
 
+    /// <summary>
+    /// Gets the date and time which was set when this <see cref="TimeProvider"/> was initialized.
+    /// </summary>
+    public DateTimeOffset StartTime { get; }
+
     /// <summary>
     /// Gets the frequency of <see cref="GetTimestamp"/> of high-frequency value per second.
     /// </summary>
@@ -44,9 +49,8 @@ public class ManualTimeProvider : TimeProvider
     /// </summary>
     /// <param name="localTimeZone">Optional local time zone to use during testing. Defaults to <see cref="TimeZoneInfo.Utc"/>.</param>
     public ManualTimeProvider(TimeZoneInfo? localTimeZone = null)
-        : this(Epoch)
-    {
-        this.localTimeZone = localTimeZone ?? TimeZoneInfo.Utc;
+        : this(Epoch, localTimeZone)
+    {     
     }
 
     /// <summary>
@@ -55,8 +59,8 @@ public ManualTimeProvider(TimeZoneInfo? localTimeZone = null)
     /// </summary>
     /// <param name="startDateTime">The initial date and time <see cref="GetUtcNow()"/> will return.</param>
     public ManualTimeProvider(DateTimeOffset startDateTime)
+        : this(startDateTime, TimeZoneInfo.Utc)
     {
-        utcNow = startDateTime;
     }
 
     /// <summary>
@@ -68,6 +72,7 @@ public ManualTimeProvider(DateTimeOffset startDateTime)
     public ManualTimeProvider(DateTimeOffset startDateTime, TimeZoneInfo? localTimeZone = null)
     {
         utcNow = startDateTime;
+        StartTime = startDateTime;
         this.localTimeZone = localTimeZone ?? TimeZoneInfo.Utc;
     }
 
@@ -165,13 +170,6 @@ public void Advance(TimeSpan delta)
         SetUtcNow(utcNow + delta);
     }
 
-    /// <summary>
-    /// Advance the date and time represented by <see cref="GetUtcNow()"/>
-    /// by one millisecond, and triggers any scheduled items that are waiting for time to be forwarded.
-    /// </summary>
-    public void Advance()
-        => Advance(TimeSpan.FromMilliseconds(1));
-
     /// <summary>
     /// Sets the date and time returned by <see cref="GetUtcNow()"/> to <paramref name="newUtcNew"/> and triggers any
     /// scheduled items that are waiting for time to be forwarded.

test/TimeProviderExtensions.Tests/ManualTimeProviderExtensions.cs

@@ -0,0 +1,11 @@
+namespace TimeProviderExtensions;
+
+public static class ManualTimeProviderExtensions
+{
+    /// <summary>
+    /// Advance the date and time represented by <see cref="GetUtcNow()"/>
+    /// by one millisecond, and triggers any scheduled items that are waiting for time to be forwarded.
+    /// </summary>
+    public static void Advance(this ManualTimeProvider timeProvider)
+        => timeProvider.Advance(TimeSpan.FromMilliseconds(1));
+}

test/TimeProviderExtensions.Tests/ManualTimeProviderTests.cs

@@ -81,4 +81,37 @@ await Task.Delay(TimeSpan.FromDays(1))
         }
     }
 #endif
+
+#if NET8_0_OR_GREATER
+    [Fact]
+    public async Task Callbacks_happens_in_schedule_order()
+    {
+        var sut = new SutTimeProvider();
+        var periodicTimer = sut.CreatePeriodicTimer(TimeSpan.FromSeconds(10));
+        var startTime = sut.GetUtcNow();
+        var callbacks = new List<DateTimeOffset>();
+        var callbacksTask = AsyncCallbacks(periodicTimer);
+
+        sut.Advance(TimeSpan.FromSeconds(23));
+
+        callbacks.Should().ContainInOrder(
+            startTime + TimeSpan.FromSeconds(10),
+            startTime + TimeSpan.FromSeconds(13),
+            startTime + TimeSpan.FromSeconds(20),
+            startTime + TimeSpan.FromSeconds(23));
+
+        periodicTimer.Dispose();
+        await callbacksTask;
+
+        async Task AsyncCallbacks(PeriodicTimer periodicTimer)
+        {
+            while (await periodicTimer.WaitForNextTickAsync().ConfigureAwait(false))
+            {
+                callbacks.Add(sut.GetUtcNow());
+                await sut.Delay(TimeSpan.FromSeconds(3));
+                callbacks.Add(sut.GetUtcNow());
+            }
+        }
+    }
+#endif
 }

test/TimeProviderExtensions.Tests/ManualTimeProviderTimerTests.cs

@@ -107,10 +107,10 @@ public void Change_timer()
     }
 
     [Fact]
-    public void Timer_callback_invoked_multiple_times_single_forward()
+    public void Timer_callback_invoked_multiple_times_single_advance()
     {
-        var callbackCount = 0;
         var sut = new SutTimeProvider();
+        var callbackCount = 0;
         var dueTime = TimeSpan.FromSeconds(3);
         var period = TimeSpan.FromSeconds(5);
         using var timer = sut.CreateTimer(_ => callbackCount++, null, dueTime, period);
@@ -131,7 +131,7 @@ public void GetUtcNow_matches_time_at_callback_time()
 
         sut.Advance(interval + interval + interval);
 
-        callbackTimes.Should().Equal(
+        callbackTimes.Should().ContainInOrder(
             startTime + interval,
             startTime + interval + interval,
             startTime + interval + interval + interval);

test/TimeProviderExtensions.Tests/Microsoft.Extensions.Time.Testing.Test/FakeTimeProviderTests.cs

@@ -2,6 +2,7 @@
 using SutTimeProvider = Microsoft.Extensions.Time.Testing.FakeTimeProvider;
 #else
 using SutTimeProvider = TimeProviderExtensions.ManualTimeProvider;
+using TimeProviderExtensions;
 #endif
 
 // Licensed to the .NET Foundation under one or more agreements.